The present invention relates to chair controls. Chair controls are mechanisms which control the rate of tilting of a chair when a user leans back in the chair. They typically comprise a stationary member adapted for mounting on a pedestal base, at least one tiltable member pivotally mounted relative to the stationary member and an energy storing source or bias means operably mounted between the tiltable member and the stationary member. A chair back or chair seat is typically joined to the tiltable member. As one leans back in the chair, the tiltable member pivots relative to the stationary member and the bias means controls the rate of tilting. When one stops leaning back in the chair, the bias means returns the tiltable member to its normal position.
Usually, a chair control includes some means for adjusting the pretension of the bias means. The greater the pretension on the bias means, the more force it takes to lean back in a chair to which the chair control is mounted. Usually, this adjustment means comprises a threaded bolt with a hand wheel on one end. The threaded bolt threads into a threaded member which is operably attached to the bias means. When one turns the bolt using the hand wheel, one tightens or loosens the tension on the bias means. Examples of such devices include the following patents to Doerner, U.S. Pat. Nos. 3,339,973, 3,601,444 and 3,603,640, issuing Sept. 5, 1967, Aug. 24, 1971 and Sept. 7, 1971 respectively.
In his U.S. Pat. No. 3,881,772, Mohrman associated with a hand wheel by providing a conventional bolt with a slotted head for receiving a screw driver. This mechanism is, however, inconvenient. Tilting chairs to which chair controls are usually applied are most often found in offices. Screw drivers most often are not found in offices.